From U.S. Pat. No. 4,865,212 there is disclosed a rim structure for a metal container having a rim that is an integral part of the container cylindrical sidewall. One of the drawbacks of this known rim is that the rim has not enough rigidity in the container mouth, and any accidental fall or dropping of a full container may cause the lid to be opened because the mouth may be detrimentally strained.
With the rim structure of the present invention, more compact rigidity in the container mouth is obtained which is only comparable to that achieved by conventional rims which are separately produced and which must then be separately secured to the edge of the container sidewall using a special operation. However, the rim structure of this invention preserves the low-cost advantages provided when the rim is incorporated to the container in a single operation.
Additionally, with the rim structure of the present invention, due to the particular rim configuration provided, a more specific lid airtight seal and a better lid holding in its sealing position is obtained so as to better resist blows or drops which might tend to cause accidental opening.
Lastly, with the improved rim structure all of the rim outside visible portions have the same finished appearance as that of the container sidewall, thereby giving the rim an improved aesthetic appearance relative to most known metal containers. Most known metal containers are generally provided with an appearance or rim color quite different to that of the container external walls due to these components being separately made.
In the mouth of the container of this invention, rigidity is provided by specific edge bending of the container sidewall making up the rim and shaped by an outwardly projecting length with a tilt of about 45.degree., this length being radially inwardly folded over onto itself and then vertically upwardly raised and radially outwardly folded to define a generally triangle-shaped cross section. The top free end of the triangle is extended according to a vertically upwardly short length, being afterwards inwardly folded over onto itself so that a rounded edge can be shaped.
This peculiar configuration determines an internal step close to the mouth, its top portion being flexible or resilient, and this resiliency being provided by the free outwardly deflection of the vertically internal length determining said step. This resiliency allows an annular projection, as provided on the container lid outside sidewall, to be snap-fitted through the step length, with the projection snapping under the stepping edge and being then fixed to create a highly resistant snap-fit against accidental opening.